Stanadyne RGX 12mm High-Pressure Fuel Pump for GM LTx

Purpose-Built Direct-Injection Fueling for Serious GM LTx Power

The Stanadyne RGX is not a modified production pump. It is a purpose-built 12.0 mm high-pressure direct-injection pump engineered for builders, tuners and race teams pushing GM Gen V LTx combinations beyond the practical limits of OE-style fuel-pump capacity.

Stanadyne validated the RGX through more than 500 hours of durability testing on both 7.85 mm and 8.2 mm fuel-lobe configurations. The redesigned lower assembly, upgraded spring system and optimized internal discharge passages are built to maintain stable, efficient fuel delivery under high lift, high engine speed and wide-open-throttle operation.

RGX Performance Highlights

• Purpose-built 12.0 mm plunger high-pressure pump
• DLC-coated bore and piston
• 443 liters per hour at 7,000 engine rpm with a 7.85 mm fuel lobe
• Recommended fuel-lobe lift: 7.85 mm
• Maximum tested fuel-lobe lift: 8.2 mm
• Engine-speed capability up to 8,000 rpm
• Compatible with production LT1 and LT4 pump lobes and properly configured aftermarket high-lift lobes
• Improved inlet orientation for LT2 packaging
• Optimized discharge passages for increased high-rpm and WOT efficiency
• 100% tested for performance and functionality
• Compatible with gasoline, E10 through E85 and M15
• Designed for naturally aspirated, supercharged and turbocharged combinations

Pressure and Supply Requirements

• Recommended operating pressure: up to 250 bar / 3,600 psi
• Low-side fuel pressure of at least 70 psi is required to achieve maximum output
• The complete system must be sized correctly, including low-side pump capacity, injectors, commanded rail pressure and calibration

Critical Installation Requirements

This pump is not a simple bolt-on-and-go installation. Correct installed height and plunger preload must be measured and verified before final installation.

• Required installed plunger preload: 1.20-1.80 mm / .047-.070 inch
• Recommended lobe lift: 7.85 mm; maximum tested lift: 8.2 mm
• Do not use a lash cap. Stanadyne specifically prohibits lash-cap installation because immediate pump and/or engine failure may occur.
• If preload is too high, additional .012-inch / 0.3 mm gaskets are used to reduce preload
• If preload is too low, the pump flange may require professional machining to achieve the required range
• Apply blue threadlocker and torque the pump bolts evenly to 25 Nm / 18 ft-lb
• Do not allow the plunger to bottom out

Wrong preload can cause pump failure, loss of plunger-to-lifter contact at high rpm or internal piston contact. Installation measurements must be submitted through Stanadyne's RGX installation-validation portal to register the pump and support any future warranty consideration.

Open Stanadyne RGX Installation Validation and Product Registration

Technical Documents

Open RGX Technical Details in a New Tab

Open RGX Preload Requirements in a New Tab

Professional Installation Strongly Recommended

Fuel-system capability, injector capacity, camshaft fuel-lobe geometry, rail-pressure strategy and tuning must be evaluated as a complete package. SMG Speed Shop and North Texas High Performance can supply and install the supporting low-side system, injectors and calibration components required for a properly engineered GM LTx fuel system.